1. Field of the Invention
This invention relates to high speed data transmission networks. More particularly, the invention relates to response time measurement, in real time, for any individual transaction in a high speed data transmission network.
2. Description of the Prior Art
In many communications environments, billing customers for network usage is important, particularly the ability of a network to respond to a transaction in a timely manner. For example, a workstation could be part of a business where customers come in to make airline reservations. It is important that the reservation request receive a prompt response from a central processing center. Not only is the return information important to the customer, the response time is important to the system operator to provide an efficient dispatching of the requests. Moreover, service agreements between travel agencies and reservation systems require a quality of service and timely network response. A system and method which monitors in real time the response time characteristics of the data processing environment will provide information on the quality of service provided by the network. Also, the information can assist in establishing a better path through the communications network or more efficient dispatching of applications at the host to meet service agreement requirements.
In the prior art, the following patents are related to the problem addressed by the present invention:
U.S. Pat. No. 5,226,041 issued Jul. 6, 1993, describes a method for simulating dynamic behavior in a communications network. The number of data packets per time period are calculated and used to compute the duration needed to transmit all remaining packets. The '041 patent does not provide a system or method for measuring response time in a communication network.
U.S. Pat. No. 5,095,444 issued Mar. 10, 1992, describes measuring the internodal transmission delay in a network and not the response time to a transaction in such a network.
U.S. Pat. No. 5,307,351 issued Apr. 26, 1994, describes a data communication network which allows an adjustment of frame length so that an optimal frame size can be generated in a network to deal with the bit rate occurring in the network. While controlling frame size impacts response time, the '351 patent does not measure response time directly as required for enforcing service agreements in transaction systems.
U.S. Pat. No. 4,905,171 issued Feb. 27, 1990, discloses a performance monitor for locating performance bottlenecks and not the response time for each transaction in a communications network.
U.S. Pat. No. 5,206,888 issued Apr. 27, 1993, describes a start-stop synchronous communications speed detecting apparatus capable of detecting a communication speed without performing any software processing. The '888 patent is directed to measuring communication speed and not the response time of transactions in communication networks
U.S. Pat. No. 5,138,607 issued Aug. 11, 1992, discloses the measuring throughput of virtual circuits and not the response time of transactions in a network.
Summarizing, the prior art does not address the problem of response time measurement for any transaction in a data communications network. Moreover, the prior art does not disclose or address systems or methods for measuring response times in real time without the use of clocks. The measurement of response time in real time in data communications networks without requiring the capture of information to disk and post-processing will lower costs and improve the accuracy of measuring and modifying network performance. Such measurement information will also enable better enforcement of service agreements for customer use of such networks.